Unlike those of some marine bryozoans, phylactolaemate colonies consist of only one type of zooid, the feeding forms known as autozooids.

[2] They also reproduce asexually by a method that is unique among bryozoans and enables a colony's lineage to survive the variable and uncertain conditions of freshwater environments.

[6] Throughout summer and autumn they produce disc-shaped statoblasts, masses of cells that function as "survival pods" rather like the gemmules of sponges.

[3] When conditions improve, the valves of the shell separate and the cells inside develop into a zooid that tries to form a new colony.

A study estimated that one group of colonies in a patch 1 square meter (11 sq ft) produced 800,000 statoblasts.